Three dimensional, low friction vasoocclusive coil, and method of manufacture

ABSTRACT

The three dimensional, low friction vasoocclusive coil has a portion that is three dimensionally box or cubed shaped. The three dimensional box or cubed shaped portion will form a basket for filling the anatomical cavity at the site in the vasculature to be treated. The vasoocclusive device is formed from at least one strand of a flexible material formed to have a first inoperable, substantially linear configuration for insertion into and through a catheter or cannula to a desired portion of the vasculature to be treated, and a second operable, three dimensional configuration for occluding the desired portion of the vasculature to be treated. The vasoocclusive coil may optionally include a portion that is substantially J-shaped or helically shaped, for filling and reinforcing the three dimensional portion.

RELATED APPLICATIONS

This is a continuation of application Ser. No. 10/664,001, filed 16 Sep.2003, now U.S. Pat. No. 7,316,701, which is a continuation ofapplication Ser. No. 09/590,794, filed Jun. 8, 2000, now U.S. Pat. No.6,638,291, which is a continuation-in-part of application Ser. No.09/140,495, filed 27 Aug. 1998, now U.S. Pat. No. 6,171,326, andapplication Ser. No. 09/089,328, filed 2 Jun. 1998, now U.S. Pat. No.6,090,125, which is a continuation of application Ser. No. 08/799,439,filed 13Feb. 1997, now U.S. Pat. No. 5,766,219, which is a continuationof application Ser. No. 08/425,106, filed 20 Apr. 1995, now U.S. Pat.No. 5,645,558.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to vasoocclusive devices, and moreparticularly concerns a vasoocclusive device that has a first elongated,reduced friction configuration in which the vasoocclusive device may bedeployed through a catheter or cannula to an anatomical cavity at a sitein the vasculature to be treated, and that has a three dimensionalsecond configuration assumed by the vasoocclusive device at the site tobe treated for filling the anatomical cavity.

2. Description of Related Art

The art and science of interventional therapy and surgery hascontinually progressed towards treatment of internal defects anddiseases by use of ever smaller incisions or access through thevasculature or body openings in order to reduce the trauma to tissuesurrounding the treatment site. One important aspect of such treatmentsinvolves the use of catheters to place therapeutic devices at atreatment site by access through the vasculature. Examples of suchprocedures include transluminal angioplasty, placement of stents toreinforce the walls of a blood vessel-or the like and the use ofvasoocclusion devices to treat defects in the vasculature. There is aconstant drive by those practicing in the art to develop new and morecapable systems for such applications. When coupled with developments inbiological treatment capabilities, there is an expanding need fortechnologies that enhance the performance of interventional therapeuticdevices and systems.

One specific field of interventional therapy that has been able toadvantageously use recent developments in technology is the treatment ofneurovascular defects. More specifically, as smaller and more capablestructures and materials have been developed, treatment of vasculardefects in the human brain which were previously untreatable orrepresented unacceptable risks via conventional surgery have becomeamenable to treatment. One type of non-surgical therapy that has becomeadvantageous for the treatment of defects in the neurovasculature hasbeen the placement by way of a catheter of vasoocclusive devices in adamaged portion of a vein or artery.

Vasoocclusion devices are therapeutic devices that are placed within thevasculature of the human body, typically via a catheter, either to blockthe flow of blood through a vessel making up that portion of thevasculature through the formation of an embolus or to form such anembolus within an aneurysm stemming from the vessel. The vasoocclusivedevices can take a variety of configurations, and are generally formedof one or more elements that are larger in the deployed configurationthan when they are within the delivery catheter prior to placement. Onewidely used vasoocclusive device is a helical wire coil having adeployed configuration which may be dimensioned to engage the walls ofthe vessels.

The delivery of such vasoocclusive devices can be accomplished by avariety of means, including via a catheter in which the device is pushedthrough the catheter by a pusher to deploy the device. The vasoocclusivedevices, which can have a primary shape of a coil of wire that is thenformed into a more complex secondary shape, can be produced in such away that they will pass through the lumen of a catheter in a linearshape and take on a complex shape as originally formed after beingdeployed into the area of interest, such as an aneurysm. A variety ofdetachment mechanisms to release the device from a pusher have beendeveloped and are known in the art.

For treatment of areas of the small diameter vasculature such as a smallartery or vein in the brain, for example, and for treatment of aneurysmsand the like, micro-coils formed of very small diameter wire are used inorder to restrict, reinforce, or to occlude such small diameter areas ofthe vasculature. A variety of materials have been suggested for use insuch micro-coils, including nickel-titanium alloys, copper, stainlesssteel, platinum, tungsten, various plastics or the like, each of whichoffers certain benefits in various applications. Nickel-titanium alloysare particularly advantageous for the fabrication of such micro coils,in that they can have super-elastic or shape memory properties, and thuscan be manufactured to easily fit into a linear portion of a catheter,but attain their originally formed, more complex shape when deployed.

One conventional vasoocclusive coil is known, for example, that has athree dimensional in-filling coil configuration, formed by winding awire into a helix, and then winding the helix into a secondary formwhich forms a generally spherical shape, by winding the primary coilabout poles placed on winding mandrel. The secondary wound coil is thenannealed on the winding mandrel, and the coil is then removed from thewinding mandrel and loaded into a carrier for introduction into adelivery catheter. Another similar type of vasoocclusive device is knownthat can be formed from one or more strands, and can be wound to form agenerally spherical or ovoid shape when released and relaxed at the siteto be treated. Another implantable vasoocclusive device having multiplesecondary layers of primary windings has a final shape that is agenerally spherical coil formed of linear or helical primary coils thatare wound into a secondary form having three layers. The inner windingis wound and then the second layer formed by winding in the oppositedirection of the first layer. The final configuration is a chunky orstepped shape approximately a sphere, ovoid, or egg. Yet anotherconventional implant for vessel occlusion is made from helical elementsof metal or synthetic material by twisting or coiling the elements andforming them into a secondary shape such as a rosette or double rosettefor implantation using a catheter, and another vasoocclusive device isknown that has a final conical shape. However, due to the tendency ofsuch three dimensional shaped coils to transform into their expanded,final forms when introduced into a catheter in the body, they areinherently more difficult than a helical coil or a straight wire ormicro-cable to push through such a catheter for delivery to a site inthe vasculature to be treated, due to friction between the coil and thecatheter through which it is delivered to the site to be treated, whichcan even result in misalignment of the coil within the catheter duringdelivery.

There thus remains a need for a vasoocclusive device that has a threedimensional final form that can be used to fill an anatomical cavity ata site in the vasculature to be treated, reduces friction between thecoil and the catheter through which it is delivered to the site to betreated, and ultimately helps to prevent coil misalignment. The presentinvention meets these and other needs.

SUMMARY OF THE INVENTION

Briefly, and in general terms, the present invention provides for animproved vasoocclusive coil, that has a three dimensional box orcube-shaped portion, and a method of making the coil. The threedimensional portion will form a basket for filling the anatomical cavityat the site in the vasculature to be treated. The three dimensionalportion of the vasoocclusive coil comprises at least one strand of aflexible material formed to have an a first inoperable, substantiallylinear configuration for insertion into and through a catheter orcannula to a desired portion of the vasculature to be treated, and asecond operable, three dimensional box or cube-shaped configuration foroccluding the desired portion of the vasculature to be treated. Thissubstantially linear configuration allows for reduction of friction ofthe coil within a catheter or cannula being used to deliver thevasoocclusive coil to the site in the vasculature to be treated, andultimately helps prevent coil realignment or misalignment. The ultimatecoil volume that otherwise might be limited due to frictionalconstraints of three dimensional coils will not be compromised with thedevice of the present invention. The vasoocclusive coil may optionallyalso include a portion having a first inoperable, substantially linearconfiguration for insertion into and through a catheter or cannula to adesired portion of the vasculature to be treated, and a second operableconfiguration that is substantially J-shaped or helically shaped, forfilling and reinforcing the three dimensional box or cube-shaped basketportion, for occluding the desired portion of the vasculature to betreated, in order to combine the best qualities of a three dimensionalcoil and a J-shaped or helical coil.

The present invention accordingly provides for a vasoocclusive devicethat is adapted to be inserted into a portion of a vasculature foroccluding the portion of the vasculature for use in interventionaltherapy and vascular surgery. The vasoocclusive device comprises atleast one strand of a flexible material formed to have a firstinoperable, substantially linear configuration for insertion into andthrough a catheter or cannula to a desired portion of the vasculature tobe treated, and a second operable, three dimensional configuration foroccluding the desired portion of the vasculature to be treated. Thevasoocclusive device advantageously has a portion having a secondoperable, three dimensional box or cube shape for filling the anatomicalcavity at the site in the vasculature to be treated, and may optionallyinclude a portion having a second operable, substantially J-shape orhelical shape for filling and reinforcing the distal, three dimensionalbox or cube shaped portion when it is implanted at the site in thevasculature to be treated.

The present invention also provides for a method of making thevasoocclusive device. The method generally comprises the steps ofwinding at least one strand of a flexible shape memory material about amandrel formed of a refractory material in a three dimensionalconfiguration of the vasoocclusive coil to form a distal portion of thevasoocclusive coil; heating the at least one strand of a flexible shapememory material wound about the mandrel for a sufficient period of timeto impart the form to the shape memory material included in the deviceto form an operable, three dimensional configuration of thevasoocclusive coil; removing the vasoocclusive coil from the mandrel;and cold working the vasoocclusive coil into a desired elongatedconfiguration for placement into a catheter or cannula for use. In onepresently preferred embodiment, the mandrel about which the at least oneflexible strand forming the vasoocclusive coil is wound has asubstantially orthogonal or cubical body with a plurality of postsdisposed on the body. In a preferred aspect, six posts are disposed onthe body aligned with the three orthogonal x, y and z axes through thebody of the mandrel, for aligning and shaping the box or cube shapedportion of the vasoocclusive device as it is wound on the mandrel. Inone presently preferred embodiment, one of the posts is provided with ahandle that can optionally also be used as a mandrel for winding aportion of the vasoocclusive coil with a helical shape. In anotherpreferred aspect of the method, the step of heating comprises heatingthe at least one strand of a flexible shape memory material wound aboutthe mandrel at a temperature of about 1100° F. for at least about 4hours to impart the form to the shape memory material included in thedevice to form an operable, three dimensional configuration of thedistal portion of the vasoocclusive coil.

These and other aspects and advantages of the invention will becomeapparent from the following detailed description and the accompanyingdrawings, which illustrate by way of example the features of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross section of a vascular member with an aneurysmillustrating the approach of a vasoocclusive coil towards the aneurysm.

FIG. 2 is a side elevational view showing a first embodiment of a secondoperable, three dimensional configuration of the vasoocclusive coil ofthe invention.

FIG. 3A is a side elevational view showing a first option of the firstembodiment of FIG. 2, including a two-dimensional substantially J-shapedportion.

FIG. 3B is a side elevational view showing a second option of the firstembodiment of FIG. 2, including a helically shaped portion.

FIG. 4 is a perspective view of a radiopaque microstrand cable used informing the vasoocclusive coil according to the invention.

FIG. 5 is a cross-section at 5-5 of FIG. 4.

FIG. 6 is an alternate preferred embodiment of the invention including aplurality of radiopaque strands within the cable.

FIG. 7 is an alternate preferred embodiment of the present inventionwherein strands of the cable are arranged within an exterior bindingconsisting of multiple straps about the cable.

FIG. 8 is a perspective view of the embodiment of FIG. 7.

FIG. 9 is an alternative embodiment to the embodiment of FIG. 8 whereinthe external binding of the cable represents a sheath wound about thecable.

FIGS. 10 a and 10 b are perspectives of alternative embodiments of theembodiment of FIG. 9.

FIG. 11 is a cross-section of an alternative embodiment in which aplurality of multi-strand cables are included within an external sheathsurrounding the cable.

FIG. 12 is a perspective view of the embodiment of FIG. 11.

FIG. 13 is a perspective view of a first embodiment of a mandrel usedfor making the vasoocclusive coil according to the method of theinvention.

FIG. 14 is a plan view of the mandrel of FIG. 13.

FIG. 15 is a sectional view of the mandrel of FIG. 13 taken along line15-15 of FIG. 14.

FIG. 16 is a perspective view of a second embodiment of a mandrel usedfor making the vasoocclusive coil according to the method of theinvention.

FIG. 17 is a plan view of the mandrel of FIG. 16.

FIG. 18 is a sectional view of the mandrel of FIG. 16 taken along line18-18 of FIG. 17.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

While conventional three dimensional and spherical vasoocclusive coilshave been developed, such three dimensional shaped coils tend totransform into their expanded, final forms when introduced into acatheter in the body, making them inherently more difficult than asimple helical coil or straight wire to push through a catheter orcannula for delivery to a site in the vasculature to be treated, due tofriction between the coil and the catheter through which it is deliveredto the site to be treated, and that can even result in misalignment ofthe coil within the catheter during delivery.

As is illustrated in the drawings, the invention is accordingly embodiedin a vasoocclusive device that is adapted to be inserted into a portionof a vasculature for occluding the portion of the vasculature for use ininterventional therapy and vascular surgery. The vasoocclusive coil 1 isformed from at least one strand of a flexible material formed to have afirst inoperable, substantially linear configuration, as illustrated inFIG. 1, for insertion through a micro-catheter 2 into a desired portionof the vasculature to be treated, such as an aneurysm, or otheranatomical malformation of the vasculature to be treated, and a secondoperable, three dimensional configuration illustrated in FIGS. 2, 3A and3B, for occluding the desired portion of the vasculature to be treated.

FIG. 1 illustrates a helically wound vasoocclusive coil 1 which isformed to fit within the micro-catheter for insertion into an area uponwhich a therapeutic procedure is to be performed. FIG. 1 further shows acatheter pusher member 3 for delivering a vasoocclusive coil 1 forinsertion into an aneurysm 4 projecting laterally from a blood vessel 5.The end of the micro-catheter 2 is typically introduced into the openingof the aneurism by use of a guide wire (note shown), and the coil andpusher member are introduced into the micro-catheter to insert thevasoocclusive coil into the aneurysm. In a presently preferredembodiment, catheter pusher member to which the vasoocclusive coil ismounted is an optical fiber pusher which is attached to the coil by acollar 6 of shape memory material such as a nickel titaniumsuper-elastic alloy, or a shape memory polymer, for example. Thevasoocclusive coil is typically introduced into the aneurysm and is thenpushed from the micro-catheter until the vasoocclusive coil fills thecavity.

In one presently preferred embodiment, the shape memory collar 6 isheated to a temperature which allows it to be shrunk onto thevasoocclusive coil. The collar can be attached to optical fiber pusherby an adhesive which retains high strength at temperatures beyond theshape memory material transition point. After insertion, and when anoperator is satisfied that the device is properly deployed, light energyfrom a source of coherent light is introduced into the proximal end ofthe optical fiber (not shown) and propagated in the distal end 7 of thefiber to cause the shape memory material collar to return to itsprevious shape and release the vasoocclusive coil. Those skilled in theart will recognize that the invention can also be used with a variety ofother placement catheter systems, and it is not intended that theinvention be limited to the placement concepts illustrated by way ofexample.

Referring to FIGS. 2, 3A and 3B, the vasoocclusive device preferably hasa portion 8 having a second operable, three dimensional shape forfilling the anatomical cavity at the site in the vasculature to betreated. As is illustrated in FIG. 2, in a presently preferredembodiment, the three dimensional portion of the vasoocclusive device isorthogonal, having a box or cube shape for filling the anatomical cavityat the site in the vasculature to be treated.

As is illustrated in FIG. 3A, in one presently preferred option of theembodiment of FIG. 2, the vasooclusive device may also include a portion9 having a second operable, substantially J-shaped coil shape, forfilling and reinforcing the distal, three dimensional shaped portion 8when the vasoocclusive device is implanted at the site in thevasculature to be treated.

As is illustrated in FIG. 3B, in one presently preferred option of theembodiment of FIG. 2, the vasooclusive device may also include a portion9′ having a second operable, substantially helical coil shape, forfilling and reinforcing the distal, three dimensional shaped portion 8when the vasoocclusive device is implanted at the site in thevasculature to be treated.

In a presently preferred aspect of the invention, the vasoocclusivecoils are formed from a multi-stranded micro-cable, although thevasoocclusive coils can also be made from a single strand of a flexiblematerial formed to have an a first inoperable, substantially linearconfiguration for insertion into and through a catheter or cannula to adesired portion of the vasculature to be treated, and a second operable,three dimensional configuration for occluding the desired portion of thevasculature to be treated. The multi-stranded micro-cable may be formedfrom a wide variety of materials, including stainless steels if somesacrifice of radiopacity may be tolerated. Very desirable materials ofconstruction, from a mechanical point of view, are materials whichmaintain their shape despite being subjected to high stress. Certain“super-elastic alloys” include nickel/titanium alloys (48-58 atomic %nickel, and optionally containing modest amounts of iron); copper/zincalloys (38-42 weight % zinc); copper/zinc alloys containing 1-10 weight% of beryllium, silicon, tin, aluminum, or gallium; or nickel/aluminumalloys (36-38 atomic % aluminum). Particularly preferred are the alloysdescribed in U.S. Pat. Nos. 3,174,851; 3,351,463; and 3,753,700.Especially preferred is the titanium/nickel alloy known as nitinol.These are very sturdy alloys which will tolerate significant flexingwithout deformation even when used as a very small diameter wire.Additionally, the strand may be constructed of a polymer, such aspolyvinyl alcohol foam, for example. The wire should be of sufficientdiameter to provide a hoop strength to the resulting device sufficientto hold the device in place within the chosen body cavity withoutdistending the wall of the cavity and without moving from the cavity asa result of the repetitive fluid pulsing found in the vascular system.Should a super-elastic alloy such as nitinol be used, the diameter ofthe coil wire can be significantly smaller than that used when therelatively ductile platinum or platinum/tungsten alloy is used as thematerial of construction.

As is illustrated in FIG. 4, the vasoocclusive coils are preferablyformed from a multi-stranded micro-cable 10 that is typicallyapproximately from 0.0021 to 0.0045 inches in diameter, and comprises aplurality of flexible strands 12 of nickel-titanium alloy, with at leastone centrally, axially disposed radiopaque wire 14 which isapproximately from 0.0007 to 0.0015 inches in diameter. While the abovestated diameters represent those presently known to be compatible withthe invention, larger or smaller diameters may be useful for particularapplications.

The central radiopaque wire 14 can be formed of platinum or gold, forexample, other similar suitable radiopaque metals, or other suitabletypes of radiopaque materials, in order to provide a radiopaque markerof the deployed configuration of a device made of the cable duringvascular surgery. The radiopaque material may be a metal or a polymer.Suitable metals and alloys for the wiring include platinum group metals,especially platinum rhodium, palladium, as well as tungsten, gold,silver, tantalum, and alloys of these metals. Highly preferred is aplatinum/tungsten alloy.

There are numerous benefits to the novel construction of the inventionfor use in interventional devices and the like. By using the stranded ormicro-cable construction of the invention, a vasoocclusive device madefrom the micro-cable becomes virtually kink resistant compared to thesingle strand wires now commonly used in micro-coils. The multi-strandcable construction of the invention allows the micro-wires of the cableto slip across each other and reinforce each other rather than break ortake a set. Also, by incorporating a stranded radiopaque material suchas platinum, tungsten or gold into the cable construction, the device isradiopaque in sizes much smaller than with other constructions.

FIG. 5 is a cross-section of the micro-cable of FIG. 4 at 5-5illustrating one presently preferred arrangement of the strands withinthe cable. In this embodiment, the exterior strands 12 are formed of aresilient material chosen to provide the characteristics desired for aspecific application in interventional therapies. In a presentlypreferred embodiment, this material is a nickel titanium super-elasticalloy which is heat treated such that the alloy is highly flexible at atemperature appropriate for introduction into the body via a catheter orcannula. By choosing such a material for micro-coils and the like, thedevices formed from the micro-cable can be relatively easily placed intothe appropriate body cavity and after placement, the device will take ona shape designed to optimize the therapeutic purposes desired for thedevice. As illustrated in FIG. 5, such a cable can have a central core14 of a radiopaque material such as gold or platinum, thus dramaticallyenhancing the radiopacity of the cable. Even a solid super-elastic wireof the same diameter as the cable would have substantially lessradiopacity than the cable of the invention with the central gold orplatinum wire and the construction of the invention provides numerousother highly desirable characteristics. Among these characteristics isthe relative flexibility and resistance to kinking of the cable comparedto an equivalent single wire and substantially greater accommodation ofthe cable to bending, etc., with resultant lessening of trauma to thesurrounding tissue and ease of placement in a small body cavity.

While one presently preferred implementation of the micro-cable of theinvention has been illustrated, those skilled in the art will appreciatethat other variations of the invention may have advantages for certainpurposes. FIG. 6 is an example of one such construction 40 in whichradiopacity is more desirable than in other forms and for that reason anumber of radiopaque strands 42, in this illustration four in number,are formed into the cable along with three resilient material strands44. It will also be appreciated that a larger or smaller number ofstrands may be incorporated into a given cable and the cables may beformed of multiple cables in order to provide desired bending andstrength characteristics. It will also be appreciated by those skilledin the art that the invention is adaptable to the use of a variety ofmaterials which by themselves would not have been easily adaptable tomicro devices for interventional therapies. For instance, materials suchas copper are useful for intrauterine devices and the like, but copperwire, even when heavily alloyed, has certain limitations for use in suchdevices. By use of the present invention, composite cables incorporatingone or more strands of a desired material can be configured with otherstrands providing strength, flexibility, shape memory, super-elasticity,radiopacity or the like for previously unavailable characteristics inmicro devices.

FIG. 7 illustrates a cross-section of an additional presently preferredembodiment of the invention in which the strands 12, 14 of themicro-cable 10 are bundled and banded at intervals by bands 50 toproduce a composite banded cable 52 in order to provide increasedflexibility without unraveling or dislocation of the strands in thecable. FIG. 8 is a perspective view of the banded cable 50 of thisembodiment. While the illustrated configuration shows the strands beinglaid parallel within the cable, it is also possible in this constructionto include both twisted cables as the primary cables 10 within the outerbands 50 to form the composite cable 52. This configuration can use oneor more longitudinal strands 14 which are radiopaque, thus providing acontinuous indication of radiopacity within the cable. As a furtheralternative embodiment, it is possible for the longitudinal cable 52 tobe formed of a single inner cable 10 with bands 50.

FIG. 9 illustrates a further embodiment of the invention in whichlongitudinal strands of cables are contained within a wound cover 56 forthe purposes of providing a composite guide wire or the like 58 havingimproved torqueability. Such a construction has particular advantagesfor guidewire designs having improved radiopacity in very smalldiameters. It will be appreciated that in this configuration, as well asthe other longitudinally arranged multi-stranded cables, the number ofstrands and the degree to which they extend along the cable within thesheath is a variable which can be used to provide increased stiffness,pushability and torqueability in some sections with greater flexibilityin others. Additionally, composite cables according to the invention canincorporate additional elements normally not available in solid guidewires, such as optical, thermal or ultrasound imaging elements,therapeutic agent delivery catheters, and can take advantage ofmaterials which are not readily adaptable to prior art catheter or guidewire designs incorporating a primary wire structured element. FIGS. 10 aand 10 b illustrate a further variable available because of theinvention; the exterior wrapped cover 56 can be wound at greater orlesser intervals 60 along the outside to provide variations in thetorqueability and stiffness of the composite cable. Also, the thicknessand width of the wrapping cover 56, as well as its material compositionalong the composite guide wire 58, can offer further capabilities forcustomizing the design for various applications. These advantages can becombined with the benefits of shape memory or super-elastic alloys tocreate guidewires and other devices with heretofore unavailablecapabilities.

FIGS. 11 and 12 illustrate a cross-section of a micro-cable according tothe invention which has at least one overall exterior sheath to containthe micro-cable. The micro-cable may be made of one or more multiplestrand elements which may further include twisted or longitudinalstrands within their construction. The sheath may also be used tocontrol the torqueability characteristics of the cable, and the sheathmay be multi-layered with different materials in order to provide agraduated bending and stiffness characteristic over the length of thecable.

It will be appreciated that a three dimensional occlusive device adaptedto be inserted into a portion of a vasculature for occluding the portionof the vasculature for use in interventional therapy and vascularsurgery, can be formed as described above, from at least onemulti-stranded micro-cable having a plurality of flexible strands of aresilient material, with at least one radiopaque strand to provide aradiopaque marker for the device during vascular surgery. The occlusivedevice is configured to have a first inoperable, substantially linear,elongated configuration for insertion into and through a catheter orcannula to a desired portion of the vasculature to be treated, and asecond operable, three dimensional configuration for occluding thedesired portion of the vasculature to be treated.

In the method of making the vasoocclusive coils of the invention, amandrel is used for annealing the coils in the desired second operable,substantially orthogonal three dimensional box or cube shape. A mandrelsuitable for making such second operable, three dimensional shapedocclusive devices can be formed of a refractory material, such asalumina or zirconia, for example. The mandrel forms a support for thewinding and heat treatment of the micro-cable, plurality ofmicro-cables, or composite micro-cable occlusive device as describedabove, and ideally will not contaminate the occlusive device during heattreatment of the device.

In one presently preferred embodiment illustrated in FIGS. 13, 14 and15, one or more of the flexible strands forming the vasoocclusive coilare wound around the surface of a mandrel 70 having a substantiallyorthogonal main body 72 with six cylindrical posts 74 having a diameterslightly smaller than that of the main body, disposed on the body andaligned with the three orthogonal x, y and z axes through the body ofthe mandrel, for aligning and shaping the distal portion of thevasoocclusive device as it is wound on the mandrel.

As is illustrated in FIGS. 16, 17 and 18, in a presently preferredvariant of the embodiment of FIGS. 13, 14 and 15, the mandrel mayoptionally also include an aperture, such as a threaded aperture 78,provided in a face 80 of one of the posts 74 and coaxially aligned withthe orthogonal axis the post, for receiving a corresponding end 82 of agenerally cylindrical handle 84. The end 82 of the handle may also becorrespondingly threaded. The handle can optionally be used as a mandrelfor winding a portion of the vasoocclusive coil with a helical shape.

The surface of the mandrel may also have one or more apertures forreceiving one or more ends of the strands, to assist winding into thedesired form. The wound occlusive device is preferably heat treated at asuitable temperature and a sufficient period of time to impart the formto the shape memory material included in the device. While heattreatment at a temperature of about 1100° F. for approximately 4 hoursor more is typically sufficient to impart the form to the occlusivedevice when the shape memory material is a nickel titanium super-elasticalloy, although the temperature utilized can be substantially lowered,and the duration of heat treatment adjusted accordingly, as will beappreciated by those skilled in the art. After the heat treatment, theocclusive device is removed from the mandrel, and cold worked into thedesired collapsed elongated configuration for placement into a catheteror cannula for use. When the occlusive device reaches its destination inthe vasculature during vascular therapy, it assumes the primary shapeimparted from the heat treatment on the mandrel.

It will be apparent from the foregoing that while particular forms ofthe invention have been illustrated and described, various modificationscan be made without departing from the spirit and scope of theinvention. Accordingly, it is not intended that the invention belimited, except as by the appended claims.

What is claimed is:
 1. A vasoocclusive device that is adapted to beinserted into a portion of a vasculature for occluding a portion of thevasculature for use in interventional therapy and vascular surgery,comprising: a plurality of strands of flexible material including acentrally, axially disposed radiopaque wire, said plurality of strandsof flexible material being formed to have a first portion with a firstsubstantially linear configuration, and a second three dimensionalsubstantially cube shaped orthogonal configuration, and a secondportion, said second portion having a first substantially linearconfiguration, and a second elongated configuration including a seriesof seven helical loops, said series of seven helical loops of saidsecond portion having a free end and an end connected to said firstportion, with said series of seven helical loops extending from thesecond three dimensional substantially cube shaped orthogonalconfiguration of the first portion in said second elongatedconfiguration, said series of seven helical loops of said second portionbeing configured to extend inwardly within said first portion to filland reinforce the three dimensional substantially cube shaped orthogonalconfiguration of said first portion in said second elongatedconfiguration when the vasoocclusive device is implanted at the site inthe vasculature to be treated.
 2. The vasoocclusive device of claim 1,wherein said plurality of strands of flexible material comprises asuper-elastic material.
 3. The vasoocclusive device of claim 2, whereinsaid super-elastic material comprises a nickel titanium alloy.
 4. Thevasoocclusive device of claim 1, wherein said plurality of strands offlexible material comprises a shape memory material.
 5. Thevasoocclusive device of claim 3, wherein said shape memorynickel-titanium alloy is heat treated such that the alloy is highlyflexible at a temperature appropriate for introduction into the body viaa catheter, and after placement, the device will take on the operableconfiguration.
 6. The vasoocclusive device of claim 1, wherein saidradiopaque strand is made of platinum.
 7. The vasoocclusive device ofclaim 1, wherein said radiopaque strand is made of tungsten.
 8. Thevasoocclusive device of claim 1, wherein said radiopaque strand is madeof gold.